U.S. patent number 4,877,398 [Application Number 07/054,837] was granted by the patent office on 1989-10-31 for bracket for permitting tipping and limiting uprighting.
This patent grant is currently assigned to TP Orthodontics, Inc.. Invention is credited to Peter C. Kesling.
United States Patent |
4,877,398 |
Kesling |
October 31, 1989 |
**Please see images for:
( Certificate of Correction ) ** |
Bracket for permitting tipping and limiting uprighting
Abstract
An orthodontic bracket having a horizontal archwire slot and
wire-engaging surfaces for use in any treatment technique and
coacting with an archwire and force generating means to produce
tooth movement through crown tipping and root uprighting actions
and for defining predetermined tip values. The bracket includes
pivot edges for permitting pivotal movement between the bracket and
the archwire, and a stop for limiting over-root-uprighting. It may
also have a stop for limiting over-crown-tipping.
Inventors: |
Kesling; Peter C. (La Porte,
IN) |
Assignee: |
TP Orthodontics, Inc.
(Westville, IN)
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Family
ID: |
26716219 |
Appl.
No.: |
07/054,837 |
Filed: |
June 4, 1987 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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39530 |
Apr 16, 1987 |
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879072 |
Jun 26, 1986 |
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Current U.S.
Class: |
433/8;
433/16 |
Current CPC
Class: |
A61C
8/0053 (20130101); A61C 7/303 (20130101); A61C
8/0096 (20130101); A61C 7/22 (20130101); A61C
7/12 (20130101) |
Current International
Class: |
A61C
7/12 (20060101); A61C 7/00 (20060101); A61C
003/00 () |
Field of
Search: |
;433/8,9,10,11,15,16 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Forestadent, "Mobil-Lock Variable-Slot Bracket", May 1979..
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Primary Examiner: Mancene; Gene
Assistant Examiner: Lepiane; Adriene J.
Attorney, Agent or Firm: Zickert; Lloyd L.
Parent Case Text
This application is a continuation-in-part Apr. 26, 1988 of my
copending application Ser. No. 039,530, filed Apr. 16, 1987 and
abandoned, which is a continuation-in-part of my copending
application Ser. No. 879,072, filed June 26, 1986 and abandoned
Oct. 14, 1987.
Claims
The invention is hereby claimed as follows:
1. An orthodontic bracket mountable on the crown of a tooth and
coacting with a generally passive archwire extending substantially
parallel to the occlusal plane, said bracket having a body with a
horizontally opening archwire slot with means coacting with said
archwire for crown tipping including fulcrum means, and means
coacting with said archwire for limiting root uprighting, said
crown tipping means having at least one surface extending at an
angle relative to the occlusal plane, said means limiting root
uprighting having at least one surface extending parallel to the
occlusal plane, whereby said bracket is mesiodistally pivotal on
the archwire about a generally horizontal axis, and said slot and
archwire being sized so that the archwire substantially fills the
area between the fulcrum means and the root uprighting limiting
means when the tooth is uprighted.
2. The bracket of claim 1, wherein said means limiting root
uprighting includes diagonally opposed uprighting stops extending
parallel to said occlusal plane.
3. The bracket of claim 2, wherein said means for allowing crown
tipping includes diagonally opposed tipping stops extending at an
angle to said occlusal plane.
4. The bracket of claim 3, wherein said fulcrum means includes
diagonally opposed curvilinear faces.
5. The bracket of claim 2, wherein said fulcrum means further
includes diagonally opposed pivot edges facilitating pivotal
movement between said wire and bracket.
6. The bracket of claim 5, wherein said pivot edges are offset from
opposite sides of a vertical center line of said bracket.
7. The bracket of claim 2, which comprises a single tie wing
including said uprighting stops, diagonal tipping stops angularly
disposed to said uprighting stops, and archwire pivot edges between
said uprighting and tipping stops.
8. The bracket of claim 2, which comprises a pair of tie wings,
each of said wings including an uprighting stop, said uprighting
stops being in diagonally opposed positions.
9. The bracket of claim 2, which comprises a pair of tie wings,
each of said tie wings including an uprighting stop and a tipping
stop, said uprighting stops being in diagonally opposed positions
and said tipping stops being in diagonally opposed positions.
10. The bracket of claim 2, wherein the archwire includes parallel
opposed upper and lower flat surfaces, and said uprighting stops
include flat archwire engaging faces coacting with the archwire
surfaces to apply a predetermined torque to the tooth.
11. The bracket of claim 2, which further includes rotation
extensions at opposite sides of the bracket body.
12. An orthodontic bracket mountable on the crown of a tooth, said
bracket having a body with a horizontally opening archwire slot and
a single tie wing having gingival and occlusal tips, the
improvement being in the archwire slot for crown tipping and
limiting root uprighting, said archwire slot defined by diagonally
opposed archwire engagement faces so that, where the archwire
extends substantially parallel to the occlusal plane, mesiodistal
crown tipping forces applied to the tooth will tip the crown
relative to the archwire and root uprighting forces applied to the
tooth will upright the root until the wire is engaged by at least
some of the diagonally opposed wire engagement faces which are at
predetermined locations to ultimately position the long axis of the
crown at a desired vertical inclination, said slot including
fulcrum means, said engagement faces which position the long axis
of the crown at a desired vertical inclination extend parallel to
the occlusal plane and said other engagement faces extend at an
angle to said occlusal plane, whereby said bracket is mesiodistally
pivotal about a generally horizontal axis and said slot and
archwire being sized so that the archwire substantially fills the
area between the fulcrum means and the engagement faces limiting
vertical inclination when the tooth is uprighted.
13. An edgewise-type bracket adapted to be mounted on the crown of
a tooth such that the vertical axis of the bracket substantially
aligns with the long axis of the crown, said bracket having a body
with a horizontally opening archwire slot and a single tie wing
having gingival and occlusal tips, the improvement being in the
archwire slot that is formed for crown tipping and limiting root
uprighting, said archwire slot defined by diagonally opposed
archwire engagement faces with laterally offset archwire pivot
edges for mesiodistal pivoting of the bracket on the archwire about
a generally horizontal axis so that, where the archwire extends
substantially parallel to the occlusal plane, mesiodistal crown
tipping forces applied to the tooth will tip the crown relative to
the archwire and root uprighting forces applied to the tooth
through the bracket will upright the root until the wire is engaged
by at least some of the diagonally opposed wire engagement faces
which are at predetermined locations to ultimately position the
long axis of the crown at a desired vertical inclination, some of
the engagement faces being at a different angle to the vertical
axis of the bracket than other of said faces, said engagement faces
which position the long axis of the crown at a desired vertical
inclination extend parallel to the occlusal plane and said other
engagement faces extend at an angle to said occlusal plane.
14. The bracket of claim 13, wherein said pivot edges are
curvilinear.
15. An orthodontic bracket mountable on the crown of a tooth and
coacting with an archwire extending substantially parallel to the
occlusal plane, said bracket having a body with a horizontally
opening archwire slot and at least one tie wing, said tie wing
having gingival and occlusal tips, said archwire slot having at
least one crown tipping stop and at least one root uprighting stop,
each of said stops being at a different angle to the vertical axis
of said bracket, said crown tipping stop being at an angle to the
occlusal plane and said root uprighting stop being parallel to the
occlusal plane when the tooth is uprighted, whereby said bracket is
mesiodistally pivotal about a generally horizontal axis.
16. The bracket of claim 15, wherein the stops extend between the
mesial and distal sides of the bracket.
17. The bracket of claim 16, wherein the uprighting stop is
parallel to the top and bottom edges of said tie wing tips.
18. The bracket of claim 16, wherein the uprighting stop angle is
such as to limit uprighting of the bracket and tooth on which it is
mounted when the tooth attains the desired final tip angle relative
to the occlusal plane.
19. An orthodontic bracket mountable on the crown of a tooth and
coacting with an archwire extending substantially parallel to the
occlusal plane, said bracket including a body having a single tie
wing with a horizontally opening archwire slot, said tie wing
having gingival and occlusal tips, said tips having parallel
gingival and occlusal edges disposed to be parallel to the occlusal
plane when the tooth has been moved to the desired position, and
said archwire slot including a crown tipping surface and a root
uprighting surface to respectively limit tipping and uprighting
movements, each of said surfaces being at a different angle to the
vertical axis of the bracket, said crown tipping surface being at
an angle to the occlusal plane and said root uprighting surface
being parallel to the occlusal surface when the tooth is uprighted,
whereby said bracket is mesiodistally pivotal on the archwire about
a generally horizontal axis.
20. An orthodontic bracket mountable on the crown of a tooth, said
bracket having a body with a horizontally opening archwire slot,
the improvement being in the archwire slot for crown tipping and
limiting root uprighting, said archwire slot defined by diagonally
opposed archwire engagement faces, some of which allow tipping and
some of which limit uprighting, said faces being arranged so that,
where the archwire extends substantially parallel to the occlusal
plane, mesiodistal crown tipping forces applied to the tooth will
tip the crown relative to the archwire and root uprighting forces
applied to the tooth will upright the root until the wire is
engaged by diagonally opposed wire engagement faces which are at
predetermined locations to ultimately position the long axis of the
crown at a desired vertical inclination, said slot further
including fulcrum means, said diagonally opposed faces which allow
tipping extend at an angle to said occlusal plane and said
diagonally opposed surfaces which limit uprighting extend parallel
to the occlusal plane when the tooth is uprighted, whereby said
bracket is mesiodistally pivotal about a generally horizontal axis,
and said slot and archwire being sized so that the archwire
substantially fills the area between the fulcrum means and the
engagement faces controlling vertical inclination when the tooth is
uprighted.
21. The bracket of claim 20, wherein said diagonally opposed faces
which allow tipping include stop means defining a plane extending
at an angle to the occlusal plane.
22. The bracket of claim 20, wherein the bracket body further
includes a single tie wing.
23. The bracket of claim 20, wherein the bracket body further
includes a pair of tie wings.
Description
This invention relates in general to an orthodontic bracket for
producing tooth movement, and more particularly to an orthodontic
bracket for producing mesial-distal tooth movement through crown
tipping and root uprighting movements, and still more particularly
to an edgewise bracket for removing teeth with intraoral generated
forces, while permitting a range of free crown tipping and
producing predetermined final degree values of root uprighting
and/or torque.
The terms "tipping" and "uprighting" relate to movements of teeth
caused by the application of selected forces. Generally, "tipping"
refers to either labial-lingual or mesial-distal movement of the
crown of a tooth, while "uprighting" refers to either mesial or
distal movement of the tip (apex) of the root of a tooth. Tipping
herein will be in the mesial-distal direction unless otherwise
specified. Torque generally refers to the movement of the root of a
tooth in the labial-lingual direction as a result of forces being
applied to the crown of the tooth. Thus, crown movement will be
referred to as tipping, while root movement will be referred to as
uprighting or torquing. The use of "and/or" herein is intended to
cover three alternatives. For example, "mesial and/or distal
archwire stops" means mesial and distal archwire stops or mesial
archwire stops or distal archwire stops.
BACKGROUND OF THE INVENTION
There are a number of orthodontic techniques in use, the most
common being the edgewise and the Begg techniques. Within the ambit
of the edgewise technique, the most popular form is referred to as
the straight-wire technique, although all forms of edgewise
technique generally use edgewise brackets having horizontally
extending archwire slots, the openings of which face horizontally.
The bracket configuration for the Begg technique utilizes a
vertically extending archwire slot which permits materially greater
free tipping of teeth during treatment than heretofore known
edgewise brackets. Free tipping action with edgewise brackets is
very limited and only possible when a wire smaller than the
archwire slot is employed, so that there is a sloppy or loose fit
between the archwire and the slot.
The need for moving teeth mesial-distally is usually caused by
spaces created by small or missing teeth. It is customary in the
Begg technique to close these spaces or move teeth by first tipping
the clinical crowns toward the open area and then uprighting the
root so that the final uprighting or tip angle of the tooth is at a
predetermined inclination. For closing such open sites when using
the edgewise technique, it is customary to bodily move the teeth.
It is well known that the forces needed, discomfort, and time
required for closing spaces by tipping and uprighting movements is
much less than that required for bodily moving the teeth.
Where teeth are initially tipped and standard edgewise brackets are
mounted on the teeth to provide treatment through the edgewise
technique, it is difficult, if not impossible, to engage a
relatively large diameter or stiff archwire into the respective
archwire slots. The same problem exists if teeth with edgewise
brackets become tipped during the course of treatment. And yet,
such larger diameter, stiffer archwires are often necessary to
control the vertical and horizontal positions of the teeth in the
jaws. Therefore, weaker and more flexible archwires must be
utilized which can cause the anterior teeth to elongate. The most
common method of preventing elongation includes application of
heavy extraoral forces to the upper archwire.
If resilient archwires are deflected to fully engage edgewise slots
where teeth are tipped, the occlusal plane or level of the biting
edges of the teeth can be adversely affected by the forces applied
through these archwires. Usually, the anterior teeth are elevated
out of their sockets, resulting in an unhealthy deep anterior
overbite condition. This is one of the reasons tipping of teeth in
the edgewise technique is avoided. Moreover, the very design of the
well known edgewise bracket prevents teeth from becoming tipped
during treatment. It will be understood that the "occlusal plane"
as used herein is a plane generally containing the contact points
between the upper and lower teeth, and it generally lies ninety
degrees to the vertical lines used for references when determining
and describing the amount of tip desired for each tooth.
In Begg brackets, sometimes referred to as ribbon arch or lightwire
brackets, it is usually possible to engage larger stiffer archwires
in the archwise slots because the opening of the slots face
vertically, thereby permitting ease of archwire engagement in
brackets mounted on tipped teeth.
It has been suggested that the edgewise slot be shortened
mesiodistally or altered to define opposing one point contacts to
increase the degree of tipping. However, the former still restricts
tipping, and the latter (altered) bracket can permit free tipping
but has no ability to control or create the final, desired degree
of uprighting.
While Begg brackets that permit but limit tipping and/or uprighting
are known, edgewise brackets with similar functions are not
known.
It has also been known to use combination brackets having both
labially or horizontally facing horizontal archwire slots and
gingivally facing vertical archwire slots where the vertical slots
would be used during early stages of orthodontic treatment to allow
the crowns of the teeth to tip toward their final positions. Then
in the final stage an archwire can be deflectively received by the
horizontal slots. However, while this will tend to upright the
teeth, it will also tend to deepen the anterior bite condition and
therefore headgear for producing extraoral forces may be required
to counteract such adverse conditions. Headgear comprises using the
patient's head or neck as a point of anchorage for delivering
relatively heavy forces to the teeth.
Where combination brackets are used, it has also been suggested
that two archwires by used, one in the horizontal slots and one in
the vertical slots. A lighter more resilient archwire is deflected
to seat in the angulated horizontal slots, while a heavier stiffer
archwire is engaged without deflection into the vertical slots. The
heavy wire helps stabilize the reciprocal forces delivered to the
teeth from the lighter deflected archwire as it returns to its
passive straight arch form. The use of two archwires is cumbersome
and creates undesirable food traps.
In the edgewise procedure teeth are moved bodily in their upright
positions toward one another to close spaces. Such movement
requires two to three times as much force and time as when moving
teeth in the Begg technique by a combination of tipping and
uprighting forces. Normally, the crown tipping is followed by root
uprighting. Moreover, the bodily movement method in the edgewise
technique most often requires the application of extraoral force
supplied by headgear. Clinical experience indicates that the use of
such extraoral force has caused hundreds of soft tissue injuries
including many cases of partial and even total blindness as a
result of accidents occurring while wearing headgear.
SUMMARY OF THE INVENTION
The present invention obviates the above-mentioned difficulties in
providing an improved edgewise bracket for moving teeth to retract
teeth and/or close spaces which essentially eliminates the need to
apply extraoral force through headgear.
The present invention relates to an improved edgewise bracket.
While particularly useful for moving teeth and closing spaces in a
straight-wire technique, it can be used with any type of technique.
The bracket of the invention resembles an edgewise bracket in that
it has one or more tie wings and a horizontal labially opening
archwire slot. The archwire slot is sized and formed to receive
either a heavy or a light archwire and a heavy archwire can be
seated in the slot even when the tooth is tipped mesiodistally.
Crown tipping and root uprighting movements may be accomplished by
use of suitable elastics, springs and other auxiliaries
intraorally.
For the purpose of accommodating the use of uprighting springs and
other auxiliaries, a vertical slot can be provided in the base of
the bracket at the tooth-mounting side. The bracket of the
invention may be provided with single or twin tie wings. While an
archwire slot in a twin tie wing bracket is not continuous, it is
considered to be the archwire slot for the bracket. With respect to
either bracket, rotation control extensions extending mesially and
distally from the archwire slot may also be provided.
It is therefore an object of the present invention to provide a new
and improved edgewise bracket for moving teeth through tipping and
uprighting functions.
Another object of the present invention is in providing a new and
improved edgewise bracket for use in edgewise and other techniques
having uprighting limit surfaces that avoid overmovements.
A further object of the present invention is in the provision of a
new and improved edgewise bracket for use in moving teeth which
substantially eliminates the need to apply extraoral forces.
A further object of the present invention is in the provision of a
new and improved edgewise bracket for use in repositioning teeth
anterior-posteriorly which substantially eliminates the need to use
headgear.
Another feature of the invention is to provide an elastic ligature
having enlargements for disposition between the archwire and
bracket engaging surfaces for the purpose of either maintaining a
predetermined relation between the archwire and the bracket or
providing additional forces to move the bracket relative to the
archwire until the control surfaces seat on the archwire. The
elastic ligature may be provided in chain form where filaments or
links interconnected adjacent ligatures and where adjacent
ligatures may be mounted on adjacent brackets so that the filaments
or links additionally function to apply a closing force between the
brackets. Another form of elastic ligature includes having a sheet
or panel of material of the same type as the ligature along one
face so that when the ligature is applied to a bracket the sheet or
panel covers the outer face of the bracket to enhance the comfort
of the patient against any of the edges of the bracket and also for
the purpose of improving the aesthetics.
Another object of the present invention is in providing a new and
improved edgewise bracket for moving teeth and to be used in
conjunction therewith an elastic ligature having enlargements
functioning to either apply additional force between the archwire
and bracket to encourage crown tipping or root uprighting or to
maintain a given position of orientation between the archwire and
bracket.
Still another object of the present invention is in the provision
of a new and improved edgewise bracket for moving teeth having
rotation control extensions or wings at the mesial and/or distal
sides of the bracket along the archwire slot and which also may be
of the single or twin tie wing form.
A further object of the invention is to provide an improved elastic
ligature having a web portion that will serve to improve the
aesthetics of fixed appliances and to protect the mouth against any
sharp edges on the bracket face.
Other objects, features and advantages of the invention will be
apparent from the following detailed disclosure, taken in
conjunction will the accompanying sheets of drawings, wherein like
reference numerals refer to like parts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one form of the bracket of the
present invention;
FIG. 2 is a top plan view of the bracket of FIG. 1;
FIG. 3 is an end elevational view of the bracket of FIG. 1 taken
along line 3--3 of FIG. 2;
FIG. 4 is a front elevational view of an upper left cuspid tooth
having a bracket of the invention mounted thereon and having an
archwire secured in the archwire slot and illustrating the distal
tipping position of the crown;
FIG. 5 is a front elevational view of an upper left cuspid tooth
with the bracket of the invention mounted thereon like that
illustrated in FIG. 4 and also illustrating the use of a root
uprighting spring and the sequential movement of the tooth from a
starting position to the desired inclined position and further
illustrating the tooth in solid lines in the final desired
position;
FIG. 6 is a fragmentary view of a tooth having the bracket of the
invention mounted thereon and illustrating the use of an uprighting
spring together with the unique elastic ligature of the invention
having force module enlargements;
FIG. 7 is a plan view of the elastic ligature shown in use in FIG.
6 in a relaxed state and which is termed a "satellite ring";
FIG. 8 is a front elevational view of a modified bracket of the
invention illustrating another form of control engaging surfaces
and also the use of the unique elastic ligature shown in FIG.
7;
FIG. 9 is a perspective view of a modified bracket of the invention
with twin tie wings;
FIG. 10 is an end elevational view of the bracket of FIG. 9 taken
along line 10--10 of FIG. 11;
FIG. 11 is a front elevational view of the bracket of FIG. 9;
FIG. 12 is an end elevational view of the bracket of FIG. 9 and of
the opposite end of the bracket of FIG. 10 taken along line 12--12
of FIG. 11;
FIG. 13 is a top plan view of the bracket of FIG. 9;
FIG. 14 is a front view of a bracket according to the invention and
a ligature ring mounted in place retaining the archwire in the
bracket archwire slot wherein the ligature includes enlargements
for producing a movement force between the archwire and the bracket
and also illustrating the bracket in a position prior to
disposition in the final upright position;
FIG. 15 is a modification of the elastic ligature shown in FIG. 7
in that a link or filament is provided between two adjacent
ligatures for purposes of connecting them together and also then
applying a force between two or more adjacent teeth;
FIG. 16 is a further modification of the ligature and including a
thin web along one face to serve when the ligature is mounted on a
bracket for purposes of improving the aesthetics of the bracket and
also to assist in protecting the tissue against any sharp edges on
the bracket;
FIG. 17 is a vertical sectional view of the ligature of FIG. 16 and
taken substantially along line 17--17 thereof;
FIG. 18 is a perspective view of a modified bracket according to
the invention having a wedge-shaped archwire slot;
FIG. 19 is a front elevational view similar to FIG. 5 but
illustrating the bracket of FIG. 18 mounted on an upper right
cuspid and in combination with an archwire connected by an elastic
and an uprighting spring; and
FIG. 20 is a front elevational view of a modification which differs
from the bracket of FIG. 1 in that the faces of the archwire slot
are curvilinear, and it is designed for an upper right cuspid.
DESCRIPTION OF THE INVENTION
The improved bracket of the invention may be generally referred to
as an edgewise bracket since it includes a horizontally opening
archwire slot in its outer face and may have one or more ligature
tie wings. The archwire slot may even have torquing surfaces for
applying a predetermined torque to a tooth. While the bracket of
the invention may be used in any one of many edgewise techniques,
it may also be used in other techniques. Normally, it will be used
in a system having edgewise-type brackets.
The bracket of the invention moves teeth mesial-distally by a
combination of tipping and uprighting actions. Either round or
rectangular archwire may be used during this tooth-moving process.
Where torque action is also desired, rectangular cross-section
archwire can be used for engagement with torquing surfaces.
Teeth that require orthodontic treatment are quite often tipped
mesial-distally at the beginning of or during the course of
movement. The unique configuration of the horizontal archwire slots
of this invention permits the initial engagement of an archwire in
the brackets on such tipped teeth with little or no deflection.
This same archwire slot design permits the teeth to tip
mesialdistally during treatment without deflecting the archwire
which could require greater force to be applied and/or result in
loss of control in the vertical dimension, i.e., the undesired
depression and/or elongation of teeth.
Inasmuch as both elastic traction devices and/or springs may be
used during the tooth-moving process, and either or both of which
may apply forces of a magnitude that could overpower a highly
resilient archwire such as of the nickel titanium or metal
core-plastic type, it is advantageous to use a relatively stiff or
rigid archwire. With the bracket of the present invention, it will
be appreciated that the archwire can be disposed in substantially
parallel relation to the occlusal plane even when engaged in
mesial-distally tipped teeth. Thus, the archwire can be of a size
and stiffness compatible with the reciprocal movement forces to be
encountered so that the tipping and uprighting movements produced
will give the desired results.
The bracket of the invention can be made of a suitable metal, such
as stainless steel, and it may be machined, sintered or cast in any
known manner. The bracket may be made and then suitably secured to
a base that would be bondable to a tooth, or the bracket and base
may be cast together as a single unit. While it is preferred that
the bracket by made of metal, it will be appreciated that it could
be made of ceramic or plastic or plastic with a metal lined
archwire slot. It is important that the bracket have sufficient
strength to withstand the forces employed during the tooth-moving
process. It may also be appreciated that the bracket may otherwise
be attached to a tooth by the usual banding methods. In all cases
the bracket will be mounted to the crown of the tooth and aligned
with the long axis of the crown so that the tooth will attain the
position finally desired.
The edges of the brackets, while illustrated as being generally
sharp, would be rounded or smoothed in actual practice to be
comfortable in the mouth. Where the bracket may be cast, the edges
and sides may even be rounded or curved. As an example, the mesial
and distal sides or the occlusal and gingival edges may be curved
when cast and still retain a generally parallel appearance.
For purposes of describing the invention and for purposes of
clarity, the drawing illustrations principally relate to showing
the straight-wire technique wherein the archwire will be generally
passive and disposed in substantially parallel relation to the
occlusal plane, and the archwire slot in each bracket may be
different to achieve varying degrees of final root uprighting
according to the desires of the orthodontist and the needs of each
patient.
Referring now to the drawings, and particularly to the embodiment
of FIGS. 1 to 6, the single tie wing version of the invention is
designated generally by the numeral 15 and includes a bracket body
16 on a base 17 of the well known type that is bondable to the
crown of a tooth, as illustrated in FIGS. 4, 5 and 6. It will be
positioned on the crown preferably centered in the middle third
area of the crown between the incisal edge and the gingiva.
The bracket body 16 includes a tie wing 20 having an upper or
gingival tip 21 and a lower or occlusal tip 22. Centrally disposed
on the tie wing is a rectangular in cross section archwire slot 23
opening horizontally and having diagonally opposed uprighting stops
24 and 25. Thus, the tie wing 20 includes means in the archwire
slot 23 for receiving an archwire such as the round archwire 27
shown in FIG. 4 or the rectangular archwire 28 shown in FIGS. 5 and
6. While the archwires illustrated are of a size that essentially
fills the archwire slot, when the tooth is in the final upright
position. As mentioned, the archwires are disposed generally
parallel to the occlusal plane 30 as in the straight-wire
technique.
The body 16 of the bracket version in FIG. 1 also includes upper
and lower tipping stops 31 and 32 that may function to limit crown
tipping movement during the tooth movement process to prevent
overtipping. The surfaces of these stops are illustrated as being
flat but also may be of any other configuration and still perform
the limited tipping function. Where the surfaces are flat, they do
not normally have any torque built into them relative to the
bracket, although such could be provided if desired. The surfaces
as shown are parallel to each other as are the uprighting surfaces.
Moreover, the tipping stops are diagonally opposed on the tie wing
as viewed in elevation, such as seen particularly in FIGS. 4, 5 and
6.
Thus, an uprighting stop surface will be generally in a directly
opposed relation to a tipping stop surface, and the mesial or
distal edges of both will define the mesial and distal openings of
the archwire slot. For purposes of providing additional rotational
control, rotation wings or extensions 36 and 37 are shown at
opposite sides of the tie wing and extend from the openings defined
by the outer ends of the stops. These extensions extend the base of
the archwire slot beyond the edges of the bracket tie wing and
against which the lingual side of the archwire would bear and
engage during the coaction between the archwire and the bracket.
They would function no matter what disposition exists between the
archwire and the bracket, as illustrated in FIGS. 4, 5 and 6. It
will also be appreciated that the bracket of the invention may be
provided without these extensions as they do not affect the
function of tipping and uprighting. They only function to provide
better rotational control.
A vertical slot 40 is provided in the bracket body at the base 17
for the purpose of facilitating the anchoring of an auxiliary such
as an uprighting spring, as illustrated in FIGS. 5 and 6. It will
be appreciated, however, that the bracket of the invention is not
dependent upon having such a vertical slot, as there are other
possible methods of anchoring an uprighting spring to the bracket.
The vertical slot 40 is parallel to and coincident with the
vertical central axis of the bracket as especially shown in FIGS. 5
and 6. It will also be noted that the vertical slot 40 is disposed
behind the tips of the tie wing 20.
The bracket 15 of the invention is shown mounted to the crown 45 of
a tooth 46 in FIGS. 4, 5 and 6 so as to illustrate the tipping and
uprighting functions in the tooth-moving process. The desired
objective is to orient the crown and position it in the ideal
location, which normally involves some degree of crown tipping or
root uprighting, or a combination of both. When closing a space the
crown is first tipped toward the open site and when disposed in
that site the root is uprighted to a position where the long axis
of the crown reaches a desired tip angulation. Further, the angles
of the crown tipping stops relative to the vertical axis of the
bracket can depend upon the amount of retraction or protraction
desired for a tooth.
The angles of inclination or locations of the archwire stops will
depend upon the specific tooth for which the bracket is designed as
well as the movement function desired by the orthodontist. For
example, when the bracket is mounted on a tooth that is intended to
undergo considerable retraction in the mouth, the distal crown
tipping stop would normally have a greater angle of inclination
that when minimum retraction is desired. For a specific tooth the
angle of inclination for the root uprighting stop would tend to be
the same for all patients depending on the orthodontist's treatment
goals, while the angle of the crown tipping stop would depend upon
the amount of retraction or protraction desired for the tooth,
depending on the patient's original malocclusion. More
particularly, a bracket of the type illustrated where tipping
movement can be accomplished between the bracket and the archwire,
the crown will first be tipped mesially or distally, then held to
prevent return to its original location, while the root is
uprighted over the crown to the ideal or desired final inclination.
These so-called ideal final inclinations may differ among
orthodontists, as does beauty in the eyes of the beholder. Where
the term "angle of inclination" is used herein, it is intended to
cover positioning of a tooth vertically or at an inclined position
to vertical. However, commonly used ideal or desired angles of
inclination for each particular tooth have been proposed. The angle
of inclination is measured to the distal between the vertical axis
of the mouth and the long axis of the clinical crown of a tooth.
For example, the common ideal angles of inclination for the upper
teeth, left and right, are:
5 degrees for a central,
9 degrees for a lateral,
11 degrees for a cuspid,
2 degrees for a bicuspid, and
5 degrees for a molar.
The common inclination angles for lower teeth, left and right,
are:
2 degrees for centrals and laterals,
5 degrees for the cuspids, and
2 degrees for the bicuspids and molars.
The tooth 46 illustrated in FIGS. 4, 5 and 6 is an upper left
cuspid, and therefore the angle of inclination for the uprighting
stops is 11 degrees. Depending upon whether the bracket is designed
to accomplish average, maximum or minimum retraction or
protraction, the angle of the crown tipping stops may vary.
However, a maximum crown tipping angle may be utilized on all teeth
where the orthodontist would monitor the tipping and remove the
crown tipping forces when the desired tipping is accomplished for
each tooth. At some point after this, the uprighting of each tooth
would commence with the application of a suitable uprighting force
or forces by use of suitable intraoral force generating
devices.
The archwire 27 is retained in the archwire slot of the bracket by
a suitable ligature such as the elastic ligature 50 of the well
known type as shown in FIG. 4 that would be stretched and hooked
over the upper and lower tie wing tips 21 and 22 after the archwire
is disposed in the archwire slot. It may also be appreciated that a
suitable wire ligature may be provided, although an elastic
ligature is preferred in view of its relative ease of placement and
flexibility which more easily permits relative movement between the
bracket and the archwire. Moreover, a unique elastic ligature may
be used with the bracket of the present invention to produce
tipping or uprighting forces, as shown in Fig. 7 and hereafter
explained.
For purposes herein, the long axis of the tooth 46 represented by
the broken line 54 in FIG. 4 coincides with the long axis of the
crown 45, it being appreciated that the long axis of the tooth
extends through the crown 45 and the root 47. Not all cuspid teeth
or other teeth would have a root as straight as that illustrated.
Concern here is for providing the desired inclination of the crown,
and therefore the crown axis will most often be referred to when
relating to tooth disposition.
As seen in FIG. 4, the vertical axis of the patient's mouth is
indicated by the broken line 55 which normally is at ninety degrees
to the occlusal plane that is usually parallel to the archwire 27.
At the beginning of treatment, the long axis of the tooth
illustrated by the broken line 54 may have been substantially
vertical. The disposition of the tooth in FIG. 4 is that caused by
a tipping force to obtain distal crown tipping. Ideally, such
movement would be on the order of a swinging movement in the
direction of arrows 56 substantially about the pivot point 57 near
the root apex such as from the vertical axis 55 to the position
shown by the long axis 54 of the crown. In this position, it can be
appreciated that the archwire 27 will touch the crown tipping stops
31 and 32, which stops will then prevent further tipping even
though the tipping force is not fully expended. Thus, the tipping
stops automatically limit the tipping movement, and it may be
appreciated that the angle of these stops relative to the vertical
axis of the bracket may be whatever is desired, that is, the angle
could be greater or less than that of the tipping stops 31 and 32
of the bracket illustrated. It is also possible that depending upon
the timing between orthodontic visits that the tipping force may be
fully expended and the archwire may not fully engage the tipping
stops but that the orthodontist might remove the tipping force and
commence application of an uprighting force. In any event, as
already mentioned, overtipping can be prevented by the tipping
stops. It must be realized that the pivot point 57 or center of
rotation of tipping may occur anywhere between the root apex and
the bracket slot.
The relative movement between the bracket and the wire will be
about pivot edges or areas 59 and 60 which are respectively defined
between the surfaces of tipping and uprighting stops 31 and 24
respectively and between the tipping and uprighting stops 32 and 25
respectively, so that the pivot edges will function as a fulcrum
about which the bracket will pivot on the archwire 27. The pivot
edges are at the ends of the tipping and uprighting stops. While
these edges are illustrated to be generally sharp, they may be
rounded or the entire length of the archwire faces may be rounded
as in the embodiment of FIG. 20. The archwire will generally be
considered the reference line along and about which tipping and
uprighting occurs. The bracket and pivot edges may also move
mesially or distally along the archwire as the crown is tipped or
the root uprighted. Preferably, these pivot edges will be laterally
offset from one another, as illustrated in FIGS. 4, 5 and 6,
although it will be appreciated that they could also be vertically
coincident and still permit a degree of tipping and limited
uprighting where the pivot edges are at one side, as seen in FIG.
18.
Once the desired tipping movement has been accomplished, it is then
the objective to complete movement of the tooth to upright the root
47. One method of applying an uprighting force is by using an
uprighting spring such as the spring 63 shown in FIGS. 5 and 6.
This spring includes a power coil 64 and extending therefrom a tail
65 that would be received in the vertical slot 40 of the bracket
and a power arm 66 that would be hooked over the archwire. The
uprighting spring would function in the usual manner whereby,
mounted as shown in FIGS. 5 and 6, it would cause the root of the
tooth to upright in the direction of the arrow 67 from the broken
line position 68 through the substantially vertical position to the
broken line position 69. The final position 69 would approximate
the inclination angle desired of the particular tooth being moved,
and as previously stated for an upper cuspid tooth this could be
about 11 degrees from the vertical axis. Root uprighting movement
would generally be in the form of a pivotal movement of the tooth
substantially about the pivotal or generally horizontal axis 71
shown in FIG. 5 which would preferably be at the center of the
bracket 15. When the uprighting stops 24 and 25 would abut the
archwire 28, as in FIG. 6, uprighting movement would cease
automatically and the tooth would be in the desired inclined
position. Thus, even if the period of time between orthodontic
visits was such that further uprighting could take place, it would
not, as the bracket would prevent further uprighting.
Where there might be needed additional uprighting force or where it
may not be possible to use an uprighting spring, the unique elastic
ligature or elastic appliance of the invention could be used to
generate movement forces. This ligature is particularly shown in
FIG. 6 in mounted relation on a bracket and generally designated by
the numeral 74 and in FIG. 7 in its passive state where it is
configurated like a satellite ring. Thus, the ligature is in the
form of a ring with one or more enlargements. It could be made of
the same material as the elastic ligature 50 but would additionally
include at predetermined locations enlargements or nodules 75 and
76 that would function to produce a force when disposed between the
archwire and a portion of the bracket and compressed. While the
ligature illustrated comprises a strand with two enlargements
therealong in equally spaced apart relation, it should be
appreciated that it could be provided with but a single
enlargement. In the illustration shown in FIG. 6, that force would
produce uprighting movement as the enlargements are disposed
between the archwire 28 and the tipping stops 31 and 32.
The size of each enlargement could be such that it would be
compressed when disposed between the archwire and the tipping stops
to produce a wedge separating force between the stops and the
archwire even when the archwire is in engagement with the other
stops. The ligature would maintain the archwire in seated position
on the stops even if the uprighting spring were to fail. In this
respect, the unique elastic ligature would be a backup to the
uprighting spring. When mounted on a bracket over the wire, it
would be stretched and tight-fitting.
It will be appreciated that the ligature 74 could be mounted such
that the force nodules 75 and 76 would be disposed between the
archwire and the uprighting stops 24 and 25 if it were desired to
provide additional tipping force during the tipping movement of the
tooth.
While normally an uprighting spring will be used as a primary force
to induce movement between the bracket and the archwire, there may
be situations where only the satellite ring 74 is needed to induce
the uprighting force, as illustrated in FIG. 14.
The enlargements on the satellite ring could be more rigid than the
elastic ring itself so that a more positive application of force
would be produced by the ring. This could be accomplished by making
the enlargements harder or less elastic than the strand when the
same type of material is used for both, or by making the
enlargements of a different material altogether. While the
enlargements are shown as ball shaped, they may be oval or
otherwise shaped.
The elastic appliances or satellite rings 74 may also be provided
in chain form and interconnected by elastic filaments or links 77,
as shown in Fig. 15. While the link 77 is illustrated as being
connected between enlargement portions of adjacent rings, it will
be appreciated that the links may interconnect at other points
along the rings. The connecting link 77 may be suitably sized to
function as a force transmitting member between adjacent rings when
they are mounted on adjacent brackets. In this respect the link 77
would serve to apply a closing force between brackets and teeth on
which the brackets are mounted. In the event that the link is not
needed, it may easily be cut to separate adjacent rings. Thus, the
satellite rings may be packaged in chain form and thereafter used
singly or in plural.
The satellite ring may also be modified by adding a thin sheet or
panel 78 of elastic material, as seen in the modified satellite
ring 74a shown in FIGS. 16 and 17. The sheet 78 would be integrally
molded with the other portions of the ring and would cover along
one entire face of the ring and be positioned outwardly when the
ring is mounted on a bracket to add comfort by completely covering
the outer face of the bracket and any sharp edges, and to also
enhance the aesthetics of the bracket. The elastic material of the
ring may be clear or of any suitable color such as a tooth or cheek
color or even a bright color. As seen particularly in FIG. 17, the
sheet of material 78 is relatively thin compared to the total
front-to-back thickness of the ring and is positioned at one face
so as to not interfere with the operation of hooking the ring over
the tie wings of a bracket.
A modified bracket is illustrated in FIG. 8 and designated 15A
which differs from the bracket 15 only in the configuration of the
tipping stops that are shown to have a concave surface between the
pivot edges and the outer edges of the bracket. These surfaces 83
and 84 define modified surfaces engaging the enlargements 75 and 76
of the endless ligature 74. The enlargements would fit in tighter
against the bracket and would provide essentially the same type of
root uprighting force as provided where the stops are straight from
the pivot edges to the outer edges of the bracket, as in the
bracket 15. This embodiment also illustrates that the bracket of
the invention, relative to the shape of the part permitting
tipping, has other forms.
The twin tie wing version of the present invention is shown in
Figs. 9 to 13. This bracket is generally designated by the numeral
90, and generally, except for having plural tie wings instead of a
single tie wing, it is structured like and functions like the
single tie wing bracket 15. This bracket includes a body 91 on a
base 92 that is bondable to the crown of a tooth in the well known
manner. The body further includes parallel tie wings 95 and 96
having an archwire slot 97 defined by diagonally disposed
uprighting stops 98 and 99 and diagonally disposed tipping stops
100 and 101 which are respectively opposite uprighting stops 98 and
99, and fulcrum means in the form of pivot points 59a and 60a that
permit rotation of the bracket substantially around a generally
horizontal axis 71a in a like fashion to the operation of bracket
15, as illustrated in FIG. 5. Thus, each tie wing includes an
uprighting stop and a tipping stop.
The uprighting stops 98 and 99 are defined by flat surfaces
parallel to each other and which may have any desired torque value.
The tipping stops are ilustrated as having arcuate surfaces, as
they function only to stop movement between the bracket and the
archwire during crown tipping movement. Thus, the uprighting stops
can function not only to control root uprighting movement but can
also function to control torque. All four stops could have arcuate
or even knife-edge faces and still function to control tipping and
uprighting.
In order to provide additional rotational control, rotation
extensions or wings 104 and 105 extend from the outer edges of the
tie wings and in the area of the openings defined between the
stops. These extensions function in the same manner as those of the
single wing version already described.
A vertical slot 107 is provided in the body adjacent the base 92
for purposes of anchoring auxiliaries such as an uprighting spring
in the same manner as described with respect to the single wing
bracket version. This vertical slot is coincident with the central
vertical axis of the bracket.
Except for the increased width of the twin wing bracket 90 over the
single wing bracket 15 that will provide better rotational control,
the function of the twin wing bracket would be the same as the
single wing bracket during the movement of teeth generated from
tipping and uprighting forces. Bracket 90 illustrates that the
invention can be used in plural wing brackets as well as single
wing brackets.
While the bracket 15 is the preferred embodiment for permitting
tipping and uprighting movements along an archwire, and which
includes an archwire slot having a general propeller-life
configuration, other configurations may be employed such as the
bracket 15A in FIG. 8. Both brackets 15 and 15A include archwire
slots within which the horizontal axis 71 of the bracket is
centrally located as particularly illustrated in FIG. 5. Where it
would be desired to shift the pivot point or where it would not
make a difference as to the location of the pivot point, the
archwire slot could take a wedge-shaped configuration as
illustrated by the modified bracket 15B shown in FIGS. 18 and 19.
This bracket includes a body 115 having a single tie wing 116, with
upper and lower tie wing tips 117 and 118. A wedge-shaped archwire
slot 119 is defined by an upper tipping stop or surface 120 and a
lower uprighting stop or surface 121. As seen particularly in FIG.
19 where the bracket is mounted on a tooth and in combination with
the archwire 28 and the uprighting spring 63, the pivot point of
the bracket about which movement occurs is at the left or distal
edge of the bracket where the bracket is mounted on an upper right
cuspid and movement is produced in the direction of the arrow 122.
Once the bracket is uprighted so that the uprighting surface 121
seats on the wire 28, uprighting action ceases. It will be
appreciated that the uprighting stop 121 coacts with the archwire
to stop the movement of the tooth at its desired tip angle relative
to the occlusal. It will be further appreciated that a suitable
torquing angle may be incorported in the uprighting surface 121 to
additionally provide torquing control. While a rectangular archwire
28 is shown mounted on the bracket 15B, it will be appreciated that
for uprighting or tipping purposes the wire may be round. Further,
it will be appreciated that during tipping action the tipping
surface 120 will limit tipping action when and if it seats on the
archwire 28. While the bracket 15B is illustrated as having a
single tie wing, it will be appreciated that it may be structured
with twin tie wings if so desired in a manner as heretofore
appreciated. Further, it may be formed with more tie wing tips on
the occlusal or gingival than on the opposite side, it only being
necessary that at least one tie wing tip be at the gingival and at
least one at the occlusal.
Another modified bracket according to the invention is shown in
FIG. 20, which differs from the embodiment of FIG. 1 in that the
entire archwire bearing faces between the mesial and distal edges
of the bracket are curvilinear. This bracket is for an upper right
cuspid.
With reference to FIG. 1, the pivot edges 59 and 60 appear rather
sharp, although these edges could be somewhat rounded. These edges
may even be more rounded than shown. Nevertheless, these pivot
edges function to define a pivotal relation between the bracket and
the archwire, as illustrated in Figs. 5 and 6. Yet, it is not
necessary that the edges 59 and 60 be sharp or approach a line
configuration.
The bracket 15C includes opposed curvilinear archwire bearing
surfaces 130 and 131. These surfaces are curvilinear between the
mesial and distal sides of the bracket. Even though they are
curvilinear, the areas of the faces adjacent the mesial and distal
edges of the bracket function as stops for tipping and uprighting.
Accordingly, the areas designated as 31c and 32c will function as
tipping stops, while the areas designated 24c and 25c function as
uprighting stops. As illustrated, the archwire is shown bearing
against the uprighting stops, or more accurately the stops are
shown bearing against the archwire which normally is maintained in
the same attitude. Appreciating that movement of the bracket
relative to the wire is very slow in the orthodontic process, the
function of the bracket 15C will not differ from the function of
bracket 15. As the bracket moves relative to the wire, the archwire
faces will change their position in a rather smooth and orderly
fashion.
The tip and torque for the bracket of the present invention,
whether it be a single wing version or a double wing version, will
be designed into the bracket according to the desired end result
for any particular orthodontic treatment.
It will be understood that modifications and variations may be
effected without departing from the scope of the novel concepts of
the present invention, but it is understood that this application
is to be limited only by the scope of the appended claims.
* * * * *